Histamine in the blood

Reference values (norm) of histamine concentration: in whole blood - 180-900 nmol / l (20-100 μg / l); in the blood plasma - 250-350 nmol / l (27,8-38,9 mkg / l).

Histamine is found mainly in basophilic leukocytes and mast cells. In smaller amounts, it is found in the liver, kidneys, intestinal cells. In the human body, histamine is formed during the decarboxylation of histidine. Histamine has a vasodilating effect (lowers blood pressure), increases the permeability of the capillaries, causes a contraction of the smooth muscles of the uterus, stimulates the release of gastric juice rich in hydrochloric acid. In the blood, histamine is in a protein-related form. The excess of histamine in the blood quickly disappears in the process of metabolism. Accumulation of histamine in the body can lead to pathological phenomena. Histamine is released from cells during anaphylactic and allergic reactions (immediate-type hypersensitivity mediator).

All types of allergic reactions are accompanied by an increase in the concentration of histamine, the magnitude of the increase in the level of histamine is judged on the degree of their severity. An increase in the concentration of histamine in the blood is also detected in carcinoids of the stomach and small intestine, mastocytoma, chronic myeloid leukemia, true polycythemia.

The relationship between the increase in the concentration of histamine in the blood plasma and its biological effect

The amount of histamine increase, μg / l	Biological effect
0-1	No
1-2	Increased gastric secretion of HCL
3-5	Tachycardia, skin reaction
6-8	Reduction of blood pressure
7-12	Bronchospasm
> 100	Heart failure